Plunger valve for a propane carburetor

ABSTRACT

A plunger valve. The plunger valve includes a body, where the length of the body is between 13 millimeters and 20 millimeters. The plunger valve also includes a set of flutes on the body. The set of flutes includes at least four flutes. The set of flutes are each symmetrically spaced about the axis of the needle-shaped plunger. The plunger valve further includes a conical tip.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application Ser. No. 61/695,226 filed on Aug. 30, 2012, whichapplication is incorporated herein by reference in its entirety.

This application is a continuation-in-part of, and claims the benefit ofand priority to, U.S. Non-Provisional patent application Ser. No.12/983,795 filed on Jan. 3, 2011, which application is incorporatedherein by reference in its entirety.

U.S. Non-Provisional patent application Ser. No. 12/983,795 claims thebenefit of and priority to U.S. Provisional Patent Application Ser. No.61/291,991 filed on Jan. 4, 2010, which application is incorporatedherein by reference in its entirety.

BACKGROUND OF THE INVENTION

Gasoline carburetors have been used extensively in internal combustionengines. Small engines and large engines have both been designed withcarburetors to provide the fuel and air mixture needed to power theengine. In particular, the engine pulls in a fuel and air mixture fromthe carburetor where it is combusted, producing mechanical power. Thecarburetor, in turn, pulls in fuel and air in the correct ratio andmixes them. Small engines, in particular, benefit from the relativesimplicity of the carburetor and the mechanical reliability of thecarburetor over long periods of time.

Gasoline, as a fuel, however, has a number of drawbacks. For example,gasoline engines, especially small engines, may need to be primed andproperly choked to allow the engine to start. Over priming of the enginecan flood the engine. Once the engine has been flooded, the operatormust generally wait for a period of time for the excess gasoline toevaporate from the combustion chamber before attempting to once againstart the engine.

In addition, gasoline does not work well as a fuel at coldertemperatures. In particular, in colder applications engines often willnot start on their own. Instead the engine must be heated beforestarting or else the gasoline will not ignite. I.e., the operator mustturn on a heater, either electric or using some other fuel source, whichheats the engine for a time before turning on the engine. This can leadto unacceptable delays.

Further, gasoline produces a high amount of carbon dioxide emissions.Carbon dioxide is considered by some to be a greenhouse gas, the excessproduction of which is implicated in global warming. In addition,gasoline can contain a number of other pollutants, such as sulfur,carbon monoxide, nitrogen oxides and hydrocarbons, which can be releasedinto the atmosphere when the gasoline is combusted. The production ofthese pollutants has become highly regulated by a number of governmentsbecause of their adverse environmental effects.

Moreover, gasoline makes for difficult throttle control. That is, slightchanges in the throttling of gasoline engines can make for large changesin the power produced in the engine. Additionally, the ratio of gasolineto air is quite sensitive, making precise throttling adjustments withgasoline engines difficult. This is particularly true at lowertemperatures. The ratio of gasoline to air needs to be higher at lowertemperature and lower at higher at lower temperatures, making the enginedifficult to control at times, especially in cold weather applications.This can be especially troublesome when precise engine control isrequired.

Finally, gasoline which is spilled can contaminate the immediate area.The gasoline can evaporate into the atmosphere where it is a pollutant.Alternatively, the gasoline can foul other equipment. For example, inice fishing a drill is used to drill through the ice to reach water. Ifthe ice fisherman spills gasoline or gets it on his hands or otherwisespreads it such that the gasoline gets on the fishing equipment, theequipment is fouled and cannot be used until the equipment is cleaned.

There are other fuels available for engines. For example, natural gas,propane and other volatile hydrocarbons are readily available. Becausethey are gases when not stored under pressure the chances ofcontamination are much lower. Additionally, engines using volatilehydrocarbons do not need to be primed, as the fuel naturally and quicklydiffuses to the combustion chamber. Further, the operating temperatureranges of these fuels are much larger and the throttle control may bemuch better. However, standard carburetors are poorly suited for propaneengines and engines which use other volatile hydrocarbons. The ratio offuel to air in these engines can vary dramatically from the ratio usedin a gasoline engine.

Accordingly, there is a need in the art for a carburetor which workswith non-gasoline engines. Further, there is a need in the art for thecarburetor to provide accurate throttle control for the engine, even atlower temperatures. In addition, there is a need in the art for acarburetor which works with fuels that are unlikely to contaminate otherequipment.

BRIEF SUMMARY OF SOME EXAMPLE EMBODIMENTS

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential characteristics of the claimed subject matter, nor is itintended to be used as an aid in determining the scope of the claimedsubject matter.

One example embodiment includes a plunger valve. The plunger valveincludes a body, where the length of the body is between 13 millimetersand 20 millimeters. The plunger valve also includes a set of flutes onthe body. The set of flutes includes at least four flutes. The set offlutes are each symmetrically spaced about the axis of the needle-shapedplunger. The plunger valve further includes a conical tip.

Another example embodiment includes a propane carburetor. The propanecarburetor includes a propane intake. The propane intake allows propaneto enter the carburetor. The propane intake includes a plunger valve.The plunger valve includes a body, where the length of the body isbetween 13 millimeters and 20 millimeters. The plunger valve alsoincludes a set of flutes on the body. The set of flutes includes atleast four flutes. The set of flutes are each symmetrically spaced aboutthe axis of the needle-shaped plunger. The plunger valve furtherincludes a conical tip. The propane carburetor also includes an airintake, where the air intake allows air to enter the carburetor. Thepropane carburetor further includes a mixing chamber, where the propaneentering the carburetor through the propane intake and the air enteringthe carburetor through the air intake are mixed in the mixing chamber.

Another example embodiment includes a propane carburetor. The propanecarburetor includes a fuel chamber, where the fuel chamber is configuredto store propane prior to mixing and a propane intake, where the propaneintake allows propane to enter the fuel chamber. The propane carburetoralso includes a diaphragm between the fuel chamber and an externalenvironment and a lever, where a first end of the lever is engaged bythe diaphragm. The propane carburetor further includes a plunger valve.The plunger valve is activated by a second end of the lever and includesa body, where the length of the body approximately 16.5 millimeters. Theplunger valve also includes a set of flutes on the body. The set offlutes includes at least four flutes each symmetrically spaced about theaxis of the needle-shaped plunger. The plunger valve further includes aconical tip. The propane carburetor additionally includes an air intake,where the air intake allows air to enter the carburetor and a mixingchamber, where the propane entering the carburetor through the propaneintake and the air entering the carburetor through the air intake aremixed in the mixing chamber. The propane carburetor moreover includes apassage from the fuel chamber to the mixing chamber.

These and other objects and features of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify various aspects of some example embodiments of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only illustrated embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1A illustrates a side view of a propane carburetor;

FIG. 1B illustrates a perspective view of the propane carburetor;

FIG. 1C illustrates an alternative side view of the propane carburetor;

FIG. 2 illustrates a cut away view of the propane carburetor;

FIG. 3A illustrates a side view of the disk actuator in idle position;

FIG. 3B illustrates a perspective view of the disk actuator in idleposition;

FIG. 4A illustrates a side view of the disk actuator at full throttle;

FIG. 4B illustrates a perspective view of the disk actuator at fullthrottle;

FIG. 5A illustrates a first side of the diaphragm of the carburetor;

FIG. 5B illustrates the opposite side of the diaphragm of thecarburetor;

FIG. 6 illustrates the carburetor of FIG. 5 with the diaphragm removed;

FIG. 7 illustrates the carburetor of FIG. 6 with the plunger valveremoved;

FIG. 8A illustrates a side view of the plunger valve; and

FIG. 8B illustrates an end view of the plunger valve.

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

Reference will now be made to the figures wherein like structures willbe provided with like reference designations. It is understood that thefigures are diagrammatic and schematic representations of someembodiments of the invention, and are not limiting of the presentinvention, nor are they necessarily drawn to scale.

I. PROPANE CARBURETOR

FIGS. 1A, 1B and 1C illustrate an example of a propane carburetor 100.FIG. 1A illustrates a side view of the propane carburetor 100; and FIG.1B illustrates a perspective view of the propane carburetor 100; andFIG. 1C illustrates an alternative side view of the propane carburetor100. In at least one implementation, the propane carburetor 100 (alsocarburettor or carburetter) is a device that blends air and propane foran internal combustion engine. In particular, the propane carburetor 100mixes propane and air in a predetermined ratio and allows the mixture toflow into an internal combustion engine where it can be converted intomechanical energy. One of skill in the art will appreciate that althoughpropane is treated as exemplary herein, the propane carburetor and anyother parts in the specification and the claims can be used with otherfuel types, such as other volatile hydrocarbons, unless otherwisespecified.

In at least one implementation, propane can offer a number of benefitsover other fuels. In particular, the engine can be started withoutpriming, choking or the risk of flooding. Additionally or alternatively,propane has a wide operating range. In particular, propane remains aneffective fuel between temperatures of −25 degrees Celsius or lower and35 degrees Celsius. Further, propane produces fewer emissions than otherfuels and does not leave contaminants if spilled.

FIGS. 1A, 1B and 1C show that the propane carburetor 100 can include apropane intake 105. In at least one implementation, the propane intake105 allows propane to enter the propane carburetor 100. The propane willenter a mixing chamber within the propane carburetor 100. The flow ofpropane does not need to be forced or pumped, as the flow of air in themixing chamber and the vapor pressure of the propane will create apressure gradient which causes the correct amount of propane into themixing chamber, as discussed below.

FIGS. 1A, 1B and 1C also show that the propane carburetor 100 caninclude an air intake 110. In at least one implementation, the airintake 110 allows air to enter the propane carburetor 100. One of skillin the art will appreciate that air can refer to any gas mixture which,when mixed with the propane, will allow the propane to undergocombustion. For example, the air can include air from the atmosphere ofsome other gas which includes oxygen for propane combustion.

In at least one implementation, the propane carburetor 100 can includean outlet. The outlet can allow the mixed propane and air to exit themixing chamber. I.e., the outlet provides the propane and air mixture tothe combustion chamber in an engine, where a spark is introduced and thepropane is combusted and mechanical energy is produced. In particular,the outlet can be connected to the mixing chamber and the combustionchamber, such that the propane and air mixture can be drawn into thecombustion chamber as needed for the engine to produce the requiredpower.

FIGS. 1A, 1B and 1C further show that the propane carburetor 100 caninclude a disk actuator 115. In at least one implementation, the diskactuator 115 can control the flow of propane and air into the mixingchamber. In particular, the disk actuator 115 can control the air flowinto the mixing chamber which, in turn, controls the propane flow intothe mixing chamber, as described below. I.e. the disk actuator 115 canbe connected to the throttle or throttle cable, allowing the operator tocontrol the power output of the engine.

FIGS. 1A, 1B and 1C additionally show that the propane carburetor 100can include cover 120. The cover 120 allows the diaphragm and valvesbelow the cover to remain sealed. I.e., the cover 120 holds thenecessary parts under the cover in the correct place during operation.

FIGS. 1A, 1B and 1C moreover show that the propane carburetor 100 caninclude an aperture 125 in the cover 120. The aperture 125 allowsoutside air to pass through the cover 120. I.e., air can freely flowthrough the aperture 125 such that the air pressure on both sides of thecover 120 remains equal at all times. That is, the air pressure justbelow the cover 120 is the ambient air pressure regardless of what theactual value of the ambient pressure.

FIG. 2 illustrates a cut away view of the propane carburetor 100. Thecut-away view can be used to illustrate the propane flow through thepropane carburetor 100. The propane carburetor 100 can be used to mixpropane and air to be supplied to the combustion chamber, as describedabove. In particular, the propane carburetor 100 can be configured towork effectively with propane, a fuel that most carburetors areunsuitable for mixing in the proper ratio with air.

FIG. 2 shows that the propane carburetor 100 can include a passage 205.In at least one implementation, propane can enter the propane carburetor100 through the passage 205. The flow rate of propane through thepassage 205 can be controlled by the flow of air through the propanecarburetor 100, as described below. Additionally, a needle valve can beused to control the amount of propane flowing through the passage 205,as described below. I.e., the propane can be pulled through the passage205 at a variable rate which depends on the air flow and the position ofa needle valve which provides the proper propane to air ratio based onits position and the position of the throttle.

FIG. 2 also shows that the propane carburetor 100 can include a venturi210. In at least one implementation, the venturi 210 includes aconstricted section of a pipe, shaft or other system through which afluid, such as a liquid or gas, is flowing. The constriction results ina reduction in fluid pressure. According to the laws governing fluiddynamics, a fluid's velocity must increase as it passes through aconstriction to satisfy the conservation of mass, while its pressuremust decrease to satisfy the conservation of energy. Thus any gain inkinetic energy a fluid may accrue due to its increased velocity througha constriction is negated by a drop in pressure. This reduction inpressure in the venturi 210 pulls the propane through the passage 205 inthe required amounts.

FIG. 2 further shows that the passage 205 and the venturi 210 can meetto form a mixing chamber 215. In at least one implementation, thepressure of the air entering the mixing chamber 215 through the venturi210 is lower than ambient pressure. I.e., the air that enters the airintake is at ambient pressure, as the air passes through the venturi 210the flow rate of the air is increased, but the pressure of the air isdecreased. This decrease in air pressure results in a pressure imbalancewithin the passage 205. I.e., the propane intake pressure is higher thanthe pressure of the mixing chamber 215. This pressure imbalance forcesthe propane through the passage 205 into the mixing chamber 215.

FIGS. 3A and 3B illustrate an example of a disk actuator 115 in idleposition. FIG. 3A illustrates a side view of the disk actuator 115; andFIG. 3B illustrates a perspective view of the disk actuator 115. In atleast one implementation, the disk actuator 115 is configured to controlthe flow of air and propane entering a propane carburetor, as describedabove. In particular, the disk actuator can be connected to a throttlecontrolled by an operator. The throttle can allow the operator tocontrol the amount of propane and air entering a propane carburetor,which, in turn, controls the amount of power produced by the engine.

FIGS. 3A and 3B show that the disk actuator 115 can include a disk 305.One of skill in the art will appreciate that the disk need not becircular in shape. I.e., the disk 305 can include a disk or cylinderhaving an irregular form. That is, disk 305 can be shaped such that thediameter varies in different directions from the center of the disk 305.The varying diameter can allow for a nonrotational force to be appliedto a particular portion of the disk 305 to be translated to rotationalforce. I.e., the disk 305 can include a portion that can translatelinear motion over a short range into rotational motion.

FIGS. 3A and 3B also show that the disk actuator 115 can include a shaft310. In at least one implementation, the disk 305 is attached to theshaft 310. Attaching the disk 305 to the shaft 310 can allow therotational motion induced in the disk 305 to be transferred to the shaft310. That is, if force is applied to the disk 305, the force istranslated into rotational force of the disk 305, which, in turn,rotates the shaft 310. Rotation of the shaft 310 can allow more air toenter the propane carburetor, as described below. In particular, therotation of the shaft 310 can transfer the force to the interiormechanisms of the disk actuator 115.

FIGS. 3A and 3B further show that the disk actuator 115 can include aplug 315. In at least one implementation, the plug 315 is configured toreside in a mixing chamber of a propane carburetor, such as the mixingchamber 215 shown if FIG. 2. The plug 315 can control the air flowthrough the mixing chamber which, in turn, can control the flow rate ofthe propane into the mixing chamber, as described above. For example,the plug 315 can rotate within the mixing chamber, allowing more or lessair and propane to enter the mixing chamber, as desired by the operator.

FIGS. 3A and 3B show that the plug 315 can include a channel 320. In atleast one implementation, the channel 320 can be aligned with the airintake and outlet of a propane carburetor, such as the air intake 110and the outlet of FIGS. 1A, 1B and 1C. The amount of alignment can beused to control the air flow. In particular, if the channel 320 is notaligned with the air intake, no air can flow into the mixing chamber andthe engine is, therefore, inoperable. However, if the channel 320 isaligned with the air intake to a low degree, only a small amount of airand propane can flow into the mixing chamber and the engine will producelittle power. For example, the engine may be idling or at a very lowthrottle position. In contrast, if the channel 320 is aligned to a highdegree with the air intake, then a high amount of air and propane willflow into the mixing chamber and the engine will produce a relativelyhigher amount of power.

One of skill in the art will appreciate that a force on the disk 305 canbe used to align the channel 320 with the air intake. In particular, athrottle can be connected to the disk 305. Force on the throttle can betransferred to the disk 305 which will rotate the shaft 310. This will,in turn rotate the plug and adjust the alignment between the channel 320with the air intake, which adjusts the amount of air and propaneintroduced into the combustion chamber. Thus, the operator can adjustthe amount of power by adjusting the throttle.

FIGS. 3A and 3B further show that the disk actuator 115 can include abase 325. In at least one implementation, the base 325 can surround theshaft 310. The base 325 can include a guide 327 which is pushes the disk305 away from the base 325 when the disk 305 is rotated, as describedbelow. Additionally or alternatively, the base 325 can include aprojection and the plug 315 can be mounted on the projection of the base325. The interface between the plug 315 and the base 325 can include athreading. The threading can include a helical structure used to convertbetween rotational and linear movement or force. The conversion of forceby the threading can bias the engine toward an idling position, asdescribed below.

FIGS. 3A and 3B further show that the disk actuator 120 can include acompressed spring 330. In at least one implementation, the compressedspring 330 is configured to push the plug 315 away from the base 325along the shaft 310. That is, unless there is a force which overcomesthe force provided by the compressed spring 330, the compressed spring330 will push the plug 315 away from the base 325 until rotational orlinear motion of the plug 315 is prevented. For example, the movement ofthe plug 315 away from the base 325 can be prevented by the guide 327 orby a threaded interface between the plug 315 and the base 325. Thus, thespring 330 biases the channel 320 in a particular alignment relative tothe air intake.

FIGS. 3A and 3B also show that the disk actuator 115 can include an idlescrew 335. In at least one implementation, the idle screw 335 can allowa small amount of air and propane to enter the mixing chamber. Inparticular, the idle screw 335 prevents the disk 305 from rotatingcounter-clockwise, as shown in FIG. 3A, keeping a low level of alignmentbetween the channel 320 and the air intake. This allows a small amountof air and propane to continue to enter the mixing chamber and pass intothe combustion chamber.

In at least one implementation, the idle screw 335 can be configured toadjust the base alignment of the channel 320 relative to the air intake.In particular, as the idle screw 335 is screwed in, the alignmentbetween the channel 320 and the air intake can be increase. Thus, theamount of air and propane entering the mixing chamber, and therefore thecombustion chamber, is increased. In contrast, as the idle screw 335 isscrewed out, the alignment between the channel 320 and the air intakecan be decreased. Thus, the amount of air and propane entering themixing chamber, and therefore the combustion chamber, is decreased.

FIGS. 4A and 4B illustrate and example of a disk actuator 115 at fullthrottle. FIG. 4A illustrates a side view of the disk actuator 115; andFIG. 4B illustrates a perspective view of the disk actuator 115. In atleast one implementation, the disk actuator 115 at full throttle isconfigured to supply the maximum amount of air and propane to theengine. I.e., the disk actuator at full throttle allows the engine toproduce the maximum amount of power.

FIGS. 4A and 4B show that the disk 305 is rotated relative to theposition of the disk 305 as shown in FIGS. 3A and 3B. In at least oneimplementation, the throttle can be configured to position the disk inany position between the positions shown in FIGS. 3A and 3B and thepositions shown in FIGS. 4A and 4B. Additionally or alternatively, thethrottle can be configured to position the disk only in the positionshown in FIGS. 4A and 4B when force is applied to the throttle. Thisrotation of the disk 305, in turn, changes the orientation and positionof the plug 315 relative to the propane carburetor.

FIGS. 4A and 4B further show that the disk actuator 115 can include astop 405. In at least one implementation, the stop 405 is configured tostop the disk 305 as it rotates clockwise, as shown in FIG. 4A. I.e.,the disk 305 is not allowed to rotate completely about the shaft. As thedisk 305 stops rotating the channel 320 and the air intake are fullyaligned. That is, the maximum amount of air and propane enter the mixingchamber and, therefore, the combustion chamber, producing the maximumamount of power output from the engine.

FIGS. 4A and 4B also show that the disk actuator 115 can include aneedle-shaped plunger 410. In at least one implementation, theneedle-shaped plunger 410 works in conjunction with a valve seat to forma needle valve. In particular, the needle-shaped plunger 410 can includea tapered end 412 which can be inserted into the valve seat, such as theend of the passage 205 of FIG. 2, in order to form a needle valve whichcontrols the amount of propane flowing into the mixing chamber. Thedistance between the needle-shaped plunger 410 and the valve seat cancontrol the amount of propane flowing into the mixing chamber. I.e.,adjusting the needle-shaped plunger 410 can adjust the propane to airratio, as described below.

In at least one implementation, the rotation of the disk 305 adjusts theposition of the needle-shaped plunger 410 relative to the valve seat. Inparticular, as the disk 305 is rotated toward the stop 405, theneedle-shaped plunger 410 moves toward the base 325. This movement, inturn, further separates the needle-shaped plunger 410 and the valveseat, increasing the amount of propane entering the mixing chamber and,therefore, the combustion chamber.

FIGS. 4A and 4B further show that the needle-shaped plunger 410 includesa head 415. A screwdriver or other tool can be inserted into the head415 in order to change the alignment of the needle-shaped plunger 410relative to the valve seat. In particular, as the head 415 is turnedcounter-clockwise and the needle-shaped plunger 410 is retracted, thedistance between the valve seat and the plunger is increased; however,the needle-shaped plunger 410 continues to impede the flow somewhat.Thus, as the head is further turned, the flow of propane increases.Since it can take many turns of the head 415 to retract the plunger,precise regulation of the flow rate is possible. In contrast, as thehead 415 is turned clockwise the needle-shaped plunger 410 is movedtoward the valve seat, and the flow of propane is reduced. One of skillin the art will understand that the threading of the needle-shapedplunger 410 can be left-handed rather than right-handed; thereforeturning the head 415 counter-clockwise can impede the flow of propanewhile turning the head 415 clockwise can increase the flow rate of thepropane.

II. PLUNGER VALVE AND OPERATION

FIGS. 5A and 5B illustrate the carburetor 100 of FIG. 1C with the cover120 removed. FIG. 5A illustrates a first side of the diaphragm 505 ofthe carburetor 100; and FIG. 5B illustrates the opposite side of thediaphragm 505 of the carburetor 100. FIGS. 5A and 5B show that thecarburetor 100 can include a diaphragm 505. The diaphragm 505 includes athin sheet of material forming a partition. In at least oneimplementation, the diaphragm 505 can separate chambers with differentair pressures. For example, the outside of the diaphragm 505 can be incontact with the ambient air pressure that enters through the aperture125 of FIG. 1C. In contrast, the inside of the diaphragm 505 can be incontact with the “internal” pressure of the carburetor 100. The internalpressure is dictated by the movement of the engine cylinder(s).

FIGS. 5A and 5B also show that the diaphragm 505 can include a disk 510.In at least one implementation, the disk 510 can be attached to thediaphragm 505. The disk 510 can provide rigidity to the desired portionof the diaphragm 505. Additionally or alternatively, the disk 510 canprovide a surface that can interact with other portions of the diaphragm505, as described below.

FIG. 6 illustrates the carburetor 100 of FIG. 5 with the diaphragm 505removed. FIG. 6 shows that the carburetor 100 can include a fuel chamber605. The fuel chamber 605 stores fuel that remains available for theengine. I.e., as the carburetor is required to provide a fuel-airmixture to an engine, the fuel is drawn from the fuel chamber 605 downthe passage 205 of FIG. 2.

FIG. 6 also shows that the carburetor 100 can also include a lever 610.In at least one implementation, the lever 610 can include a beam orrigid rod pivoted at a fixed hinge, or fulcrum. A first end of the lever610 (toward the middle of the mixing chamber 605 as shown in FIG. 6) isbiased upward by a spring (as can be seen in FIG. 2). As the diaphragm505 of FIG. 5 moves inward under pressure the disk 510 of FIG. 5 ispressed against the first end of the lever 610 causing it to move aboutthe fulcrum.

FIG. 6 further shows that the carburetor 100 can include a plunger valve615. The plunger valve 615 controls the flow of fuel into the fuelchamber 605. In particular, as the first end of the lever 610 is presseddownward, the other end rises opening the plunger valve 615. While theplunger valve 615 is open, the fuel flows past the plunger valve 615,entering the fuel chamber 605.

FIG. 7 illustrates the carburetor 100 of FIG. 6 with the plunger valve615 removed. FIG. 7 shows that the carburetor 100 can include a seat705. The seat 705 is configured to receive the plunger valve 615. Inprior configurations, the seat 705 was a simple opening. I.e., the seat705 was flat with a hole in the middle. However, operation of thecarburetor 100 is improved if the shape is changed to match the shape ofthe plunger valve 615, as described below.

FIGS. 8A and 8B illustrate an example of a plunger valve 615. FIG. 8Aillustrates a side view of the plunger valve 615; and FIG. 8Billustrates an end view of the plunger valve 615. The size and the shapeof the plunger valve 615 can be critical for proper operation of thecarburetor. For example, in a series of tests over 1000 carburetors in aprior configuration were tested for correct operation. The failure rateof the tests was over 300 carburetors (i.e., 30%) which malfunctioned athigh rpms. In addition, problems could arise later during operation andappeared to be random failure.

Multiple testing and modification of parts did not result insatisfactory progress in preventing failures. After much experimentationit was discovered that the reduction in performance was the result of aflutter in the diaphragm 505 of FIG. 5. After extensive testinginvolving multiple changes to various portions of the carburetorincluding the diaphragm 505 of FIG. 5 changes were made to the plungervalve 615 which reduced the failure rate to less than one percent. Thesechanges reduced binding and made the movement of the plunger valve 615much smoother during operation. Accordingly, these changes are criticalto proper operation of the carburetor.

FIGS. 8A and 8B show that the plunger valve 615 can include a body 805.The body 805 can be the main portion of the plunger valve 615. I.e., thebody 805 can include the central portion of the plunger valve 615. Thebody 805 can be long enough to allow for smoother operational action(less binding). For example, the body 805 can be between 13 millimetersand 20 millimeters in length (as shown by the length indicator in FIGS.8A and 8B). In particular, the body 805 can be approximately 16.5millimeters in length. As used in the specification and the claims, theterm approximately shall mean that the value is within 10% of the statedvalue, unless otherwise specified.

FIGS. 8A and 8B also show that the plunger valve 615 can include aconical shaped tip 810. The conical tip 810 can ensure that the pressurewhen seated with the valve seat remains uniform creating a better sealby the plunger valve 615. I.e., the conical tip 810 can seat uniformly,preventing any leakage and creating a more stable seal. The conical tip810 can be configured to seat in a complimentary shaped valve seat.I.e., the valve seat can likewise be conically shaped to match the shapeof the conical tip 810. Additionally or alternatively, the conical tip810 can include a material that is configured to provide a more secureseal. For example, the conical tip 810 can include a soft deformablematerial such as latex.

FIGS. 8A and 8B further show that the plunger valve 615 can include fouror more flutes 815. The four or more flutes 815 can include ribs orlongitudinal guides that are aligned longitudinally with the body 805.The four or more flutes 815 can be symmetrically spaced about the axis820 of the needle-shaped plunger. The flues 815 can be critical toproducing a smoother, more linearly-directed needle valve action. I.e.,the flutes 815 can eliminate valve binding during starting and runningoperations. During the previously described testing the plunger valve615 stuck and stuttered if fewer than four flutes 815 (such as threeflutes 815) were used. However, with the addition of a fourth flute 815the wedging was eliminated and the movement of the plunger valve 615 wassmoother, eliminating failures.

III. OPERATION OF A CARBURETOR

By way of example, operation of a carburetor will be described. I.e.,the flow of fuel, air and fuel-air mixture will be described withrespect to the carburetor as shown and described. To avoid confusion,reference numbers will be used herein which reflect the numberspreviously assigned in the Figures and the specification. However, theFigures in which the reference numbers appear will be omitted.

Internal combustion engines operate on the inherent volume changeaccompanying oxidation of a fuel. The expansion moves a cylinder backand forth in a reciprocating motion. The reciprocating motion of thepistons is translated into crankshaft rotation via connecting rod(s). Asa piston moves back and forth, a connecting rod changes its angle; itsdistal end has a rotating link to the crankshaft. A four stroke enginehas four stages which includes two reciprocations of the cylinder (henceits name), each of which occurs during one revolution of the engine. Thestages include:

-   -   1. INTAKE stroke: on the intake or induction stroke of the        piston, the piston descends from the top of the cylinder to the        bottom of the cylinder, increasing the volume of the cylinder. A        fuel-air mixture is forced by atmospheric (or greater) pressure        into the cylinder through the intake port. The intake valve(s)        then closes.    -   2. COMPRESSION stroke: with both intake and exhaust valves        closed, the piston returns to the top of the cylinder        compressing the air or fuel-air mixture into the combustion        chamber of the cylinder head. During the compression stroke the        temperature of the air or fuel-air mixture rises by several        hundred degrees.    -   3. POWER stroke: this is the start of the second revolution of        the cycle. While the piston is close to the top of the cylinder,        the compressed fuel-air mixture in a gasoline engine is ignited,        usually by a spark plug. The resulting pressure from the        combustion of the compressed fuel-air mixture forces the piston        back down toward the bottom of the cylinder.    -   4. EXHAUST stroke: during the exhaust stroke, the piston once        again returns to the top of the cylinder while the exhaust valve        is open. This action expels the spent fuel-air mixture through        the exhaust valve(s).

During the intake stroke the pressure in the combustion chamber isgreatly reduced. Therefore, pressure in the mixing chamber causes thefuel-air mixture in the mixing chamber 215 to flow into the combustionchamber. That movement causes air to flow through venturi 210 and fuelto flow through passage 205 into the mixing chamber 215.

As fuel flows down passage 205 the pressure in the fuel chamber 605 isreduced. The reduction in pressure causes the diaphragm 505 to moveinward toward the fuel chamber 605 under ambient pressure passingthrough the aperture 125 in the cover 120. The movement of the diaphragm505, in turn, moves the disk 510 inward in the fuel chamber 605 engagingthe lever 610. The plunger valve 615 is then raised allowing fuel toenter the fuel chamber 605. Because the fuel is pressurized the pressurein the fuel chamber 605 quickly reaches ambient air pressure causing thediaphragm 505 to move back out of the fuel chamber 605 disengaging thedisk 510 from the lever 610 and allowing the plunger valve 615 to close,preventing fuel from entering the fuel chamber 605.

Typical engine speeds can range from 3000 rpms (at idle speed) to 9000rpms (at full throttle). Each revolution includes two strokes of thecylinder within the combustion chamber and two revolutions result in onedraw of fuel-air mixture. Therefore, the plunger valve 615 canreciprocate between 1500 times per minute (at idle speed) and 4500 timesper minute (at full throttle) or between 25 times per second and 75times per second. This means that the plunger valve has betweenapproximately 0.013 seconds (at full throttle) and 0.040 seconds (atidle speed). Thus a delay of 1-2 thousandths of a second (0.001-0.002seconds) caused by binding of the plunger valve 615 can either flood(too much fuel) or stall (too little fuel) the engine. Therefore, thefeatures and dimensions described above are critical to proper operationof the carburetor 100. I.e., even a small amount of binding can lead tofailures in engine operation.

These failures are not applicable to engines that use other fuels, suchas gasoline, which are a liquid at ambient temperatures. I.e., the fluiddynamics of a propane gas are different than the fluid dynamics of otherfuels. Therefore, a shorter plunger valve 615, fewer flutes 815 and ahole in the seat 705 rather than a conical shape might not causeproblems in a gasoline carburetor but lead to failures in the operationof the propane carburetor 100.

IV. CONCLUSION

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A plunger valve, the plunger valve comprising: abody, wherein the length of the body is between 13 millimeters and 20millimeters; a set of flutes on the body, wherein the set of flutes:includes at least four flutes; and are each symmetrically spaced aboutthe axis of the needle-shaped plunger; and a conical tip.
 2. The plungervalve of claim 1, wherein the length of the body is approximately 16.5millimeters.
 3. The plunger valve of claim 1: wherein the conical tipincludes a soft deformable material; and further comprising a seat,wherein at least a portion of the seat is configured to receive theconical tip; and wherein the soft deformable material is configured toprovides a secure seal when pressed against the seat.
 4. The plungervalve of claim 3, wherein the portion of the seat configured to receivethe conical tip includes a conical shaped opening.
 5. A carburetorincluding the plunger valve of claim
 1. 6. A propane carburetor, thepropane carburetor comprising: an air intake, wherein the air intakeallows air to enter the carburetor; a propane intake, wherein thepropane intake: allows propane to enter the carburetor; and includes aplunger valve, wherein the plunger valve includes: a body, wherein thelength of the body is between 13 millimeters and 20 millimeters; a setof flutes on the body, wherein the set of flutes: includes at least fourflutes; and are each symmetrically spaced about the axis of the body;and a conical tip; and a mixing chamber, wherein the propane enteringthe carburetor through the propane intake and the air entering thecarburetor through the air intake are mixed in the mixing chamber. 7.The propane carburetor of claim 6 further comprising a disk actuator inthe air intake.
 8. The propane carburetor of claim 7, wherein the diskactuator includes: a disk; a shaft, wherein the shaft is connected tothe disk such that rotation of the disk causes rotation of the shaft;and a plug, wherein the plug is connected to the shaft such thatrotation of the shaft causes rotation of the plug and wherein the plugincludes: a channel, wherein the channel is configured to regulate theflow of air into a carburetor.
 9. The propane carburetor of claim 8further comprising a base, wherein the plug is capable of rotatingrelative to the base.
 10. The propane carburetor of claim 9 furthercomprising a compressed spring wherein the compressed spring isconfigured to keep the plug in its furthest position from the baseabsent an external force.
 11. The propane carburetor of claim 8, whereinthe channel includes a venturi.
 12. The propane carburetor of claim 8further comprising a needle valve, wherein the needle valve includes aneedle-shaped plunger configured to regulate the flow of propane into amixing chamber of the carburetor.
 13. The propane carburetor of claim12, wherein at least a portion the needle-shaped plunger is locatedwithin the interior of the plug.
 14. The propane carburetor of claim 12,wherein the needle-shaped plunger includes a tapered end.
 15. Thepropane carburetor of claim 14, wherein the tapered end is inserted intoa valve seat, wherein the valve seat is connected to the passage fromthe fuel chamber to the mixing chamber.
 16. A propane carburetor, thepropane carburetor comprising: an air intake, wherein the air intakeallows air to enter the carburetor; a fuel chamber, wherein the fuelchamber is configured to store propane prior to mixing; a propaneintake, wherein the propane intake allows propane to enter the fuelchamber; a diaphragm between the fuel chamber and an externalenvironment; a lever, wherein a first end of the lever is engaged by thediaphragm; a plunger valve, wherein the plunger valve: is activated by asecond end of the lever; and includes: a body, wherein the length of thebody is approximately 16.5 millimeters; a set of flutes on the body,wherein the set of flutes: includes at least four flutes; and are eachsymmetrically spaced about the axis of the body; and a conical tip,wherein the conical tip includes a soft deformable material; a mixingchamber, wherein the propane entering the carburetor through the propaneintake and the air entering the carburetor through the air intake aremixed in the mixing chamber; and a passage from the fuel chamber to themixing chamber.
 17. The propane carburetor of claim 16, wherein thediaphragm includes an attached disk, wherein the attached disk isconfigured to engage the first end of the lever.
 18. The propanecarburetor of claim 16 further comprising a spring, wherein the springis: In contact with the lever; and configured to bias the lever to holdthe plunger valve in a closed position.
 19. The propane carburetor ofclaim 16 further comprising a cover over the diaphragm, wherein thediaphragm includes: an aperture configured to allow one side of thediaphragm to remain at ambient pressure.
 20. The propane carburetor ofclaim 16, connected to a four stroke engine.